ScopeFIR can work with two filters per Project. These two filters are named " Inphase" and " Quadrature" . The two filters can be used together to form a " Complex" filter, or can be used separately as just two different real filters. Some of ScopeFIR's filter operations create a Complex filter, thus filling the coefficients of the Quadrature filter directly, but when a filter is designed using the Design Parameters Window, the design outputs go only to the Inphase filter. The Copy and Swap options can then be used to fill the Quadrature filter using coefficients stored in the Inphase filter.

Copying and swapping is useful primarily for comparing two filter designs. If you intend to design a single real (not complex) filter, you can use the Quadrature filter as a storage area to temporarily save a filter design for later comparison: just select " Copy Inphase to Quadrature" from the FIR menu. Then, to revert to the previous design, select " Copy Quadrature to Inphase" or " Swap Inphase and Quadrature" . (Note that these options save only the coefficients, not the design information shown in the Design Window, so you will lose the design parameters of the original filter in this process.)

If you have designed a true Complex filter by filling and/or mixing, you should avoid these operations because they can result in a corrupted, non-quadrature Complex filter.